Booting a PDP 11... (ah the good 'ol days)

From: Bill Pechter <pechter_at_pechter.dyndns.org>
Date: Thu Aug 5 21:43:30 1999

> Am I correct in assuming that when a PDP-11/44 finds that it has more than
> one controller in it that it can boot off of, that it drops you into the
> monitor, so you can select the device you wish to boot from?

Nope, that depends on the dipswitch settings.

You can power up boot any of the devices that you have roms for
based on the dip switch setting on the bootstrap card.

However, the default device is unit 0. (This can be changed
by a value in the switch register).

Many locations set the machine to boot drive 0 on power up so they
could autoboot on power fail if the battery backup wasn't
installed or the outage was too long for the 15 minutes (if that) of
battery backup DEC had as an option.

Some locations just droped you to the $ or _at_ prompt at all times so the
operator would boot the machine.

The $ or _at_ prompt was usually returned after the boot diags on rom ran
and verified the machine health (basic memory, registers and I/O ok).

Bill

---
  bpechter_at_shell.monmouth.com|pechter_at_pechter.dyndns.org
      Three things never anger: First, the one who runs your DEC,
      The one who does Field Service and the one who signs your check.
Received on Thu Aug 05 1999 - 21:43:30 BST

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